https://farhadnazir.com/insights/ Articles on SaaS, POS and ERP systems, Flutter and software architecture by Farhad Nazir. en https://farhadnazir.com/insights/offline-first-pos-sync/ https://farhadnazir.com/insights/offline-first-pos-sync/ How I made Asaan Optics record sales with no internet: one write path, idempotency keys end to end, a dead-letter list, stock as deltas and a per-till ledger. Wed, 11 Nov 2026 00:00:00 GMT Flutter SaaS Offline-first POS https://farhadnazir.com/insights/erp-is-workflow-engineering/ https://farhadnazir.com/insights/erp-is-workflow-engineering/ The tables are the easy part of an ERP. What I learned from the unwritten rules for attendance, performance scores, invoicing and one-transaction POS billing. Wed, 11 Nov 2026 00:00:00 GMT ERP Laravel Business software https://farhadnazir.com/insights/shipping-flutter-apps-to-windows/ https://farhadnazir.com/insights/shipping-flutter-apps-to-windows/ Lessons from building Flutter Windows apps for shops: per-user Inno Setup installers, silent updates, local SQLite, backups and thermal receipt printing. Wed, 11 Nov 2026 00:00:00 GMT Flutter Desktop apps Windows https://farhadnazir.com/insights/multi-tenant-saas-tenant-isolation/ https://farhadnazir.com/insights/multi-tenant-saas-tenant-isolation/ Tenant isolation patterns from three SaaS systems I worked on: tenant IDs from tokens, query filters, safe auth rollouts, RBAC grant ceilings and plan gating. Wed, 11 Nov 2026 00:00:00 GMT SaaS Architecture Security https://farhadnazir.com/insights/zatca-phase-2-e-invoicing-flutter/ https://farhadnazir.com/insights/zatca-phase-2-e-invoicing-flutter/ How I built ZATCA Phase 2 (Fatoora) e-invoicing in Dart for a Flutter POS: UBL 2.1 XML, hash chaining, ECDSA signing, CSID onboarding and Saudi VAT receipts. Wed, 11 Nov 2026 00:00:00 GMT ZATCA Saudi Arabia Flutter POS